Gifford C. Ewing 



Woods Hole Oceanograph ic Institution 



Woods Hole, Massachusetts 



Of the various oceanograoh Ic oarameters that one might attempt to 

 measure remotely from satellites, color has the unique advantage of 

 reacting to the bulk properties of the ocean, thus giving an estimate 

 of its biological and chemical construction. Although this information 

 is limited to the upper 10-20 meters of the sea, less than }% of the 

 total volume, nevertheless this is the part that is of most direct 

 concern to the majority of mankind. That relatively little is known 

 of the distribution of sea color is due in part to the fact that it is 

 distributed in fairly small patterns and varies with the biological 

 activity at a relatively high rate so that the low sampling rate 

 available to ships is inadequate to observe the day-to-day changes. 



Satellite oceanography is inherently directed toward observing the 

 upper layers of the sea, the part that is stirred by the wind and lit by 

 the sun. No matter what ingenious ways may be devised for probing deep 

 beneath the surface, it seems unlikely that such regions will be natural Iv 

 amenable to exploration by satellite technology. In other words, we are 

 concerned here with a specialized description of a severely limited layer 

 of the ocean. 



Fortunately, the laver of the ocean exposed to the overview is far 

 more significant than the above considerations suggest. For one thing, it is 

 the part of the ocean that overwhelmingly concerns the everyday affairs of 

 mankind. It is the site of waves, storm surges, the rise of tide, and 

 the secular changes of sea level. It covers the continental shelves 

 where oil and minerals are being recovered. It is the part of the sea that 



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